A1 Journal article (refereed)
Corticokinematic coherence is stronger to regular than irregular proprioceptive stimulation of the hand (2021)

Mujunen, T., Nurmi, T., & Piitulainen, H. (2021). Corticokinematic coherence is stronger to regular than irregular proprioceptive stimulation of the hand. Journal of Neurophysiology, 126(2), 550-560. https://doi.org/10.1152/jn.00095.2021

JYU authors or editors

Mujunen, Toni
Nurmi, Timo
Piitulainen, Harri

Publication details

All authors or editors: Mujunen, Toni; Nurmi, Timo; Piitulainen, Harri

Journal or series: Journal of Neurophysiology

ISSN: 0022-3077

eISSN: 1522-1598

Publication year: 2021

Publication date: 14/07/2021

Volume: 126

Issue number: 2

Pages range: 550-560

Publisher: American Physiological Society

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1152/jn.00095.2021

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/77166

Abstract

Proprioceptive afference can be investigated using corticokinematic coherence (CKC), which indicates coupling between limb kinematics and cortical activity. CKC has been quantified using proprioceptive stimulation (movement actuators) with fixed inter-stimulus interval (ISI). However, it is unclear how regularity of the stimulus sequence (jitter) affects CKC strength. Eighteen healthy volunteers (16 right-handed, 27.8±5.0 yrs, 7 females) participated in magnetoencephalography (MEG) session in which their right-index finger was continuously moved at ~3-Hz with constant 333 ms ISI or with 20% jitter (ISI 333±66 ms) using a pneumatic-movement actuator. Three minutes of data per condition was collected. Finger kinematics were recorded with a 3-axis accelerometer. CKC strength was defined as the peak coherence value in the Rolandic MEG gradiometer pair contralateral to the movement at 3-Hz. Both conditions resulted in significant coherence peaking in the gradiometers over the primary sensorimotor cortex. Constant stimulation yielded stronger CKC at 3 Hz (0.78±0.11 vs. 0.66±0.13, p<0.001) and its first harmonic (0.60±0.19 vs. 0.27±0.11, p<0.001) than irregular stimulation. Similarly, the respective sustained-movement evoked field was also stronger for constant stimulation. The results emphasize the importance of temporal stability of the proprioceptive stimulation sequence when quantifying CKC strength. The weaker CKC during irregular stimulation can be explained with temporal and thus spectral scattering of the paired peripheral and cortical events beyond the mean stimulation frequency. This impairs the signal-to-noise ratio of respective MEG signal and thus CKC strength. When accurately estimating and following changes in CKC strength, we suggest using precise movement actuators with constant stimulation sequence.

Keywords: kinematics; motor functions; cerebral cortex; MEG

Free keywords: proprioception; movement-evoked field; kinematics; somatosensory; jitter

Fields of science: